Add reflection to transparent cycles material
By mixing transparency and the Principled BSDF, you're defining a shader that can return either reflection, or transparency, but never both. (and since you have mix factor=0.8, it will give transparency 80% of the time). So you're making the reflections transparent along with everything else. To get your desired result, you want a shader that gives glossy reflection normally, but returns transparency to any rays the gloss doesn't catch. Two different ways you can do this:

1) Get rid of the transparent BSDF and its mix shader, just keep the Principled BSDF node for A. This will leave your glassy Principled BSDF as the only shader. Since this a refractive shader, you will need thickness on your bread bag mesh. You can use a solidify modifier to achieve this. See here if you also need the alpha channel: Render Glass like materials with Alpha Channel to composite in external app

2) If you don't want/need refraction and don't want to deal with adding thickness or messing with ways to get alpha, you can replace the first Transparent/Principled BSDF mix with the shader described here: Render Glass like materials with Alpha Channel to composite in external app